[0001] This invention relates to automotive heating, air conditioning and ventilation modules
and housings therefor.
BACKGROUND OF THE INVENTION
[0002] Automotive heating, ventilating air conditioning and ventilation modules (generally
referred to as just air conditioning modules, or abbreviated to HVAC modules) consist
basically of a hollow plastic housing within which are contained heat exchangers and
various air flow directing devices. These components, in cooperation, receive, temper,
and redirect the flow of forced air from an upstream blower to and through several
downstream outlets within the vehicle. Various valves, generally in the form of swinging
flapper doors, select the outlets to which the air ultimately exits, and these are
generally referred to as mode valves. Air can exit high to the windshield in so called
defrost and defog modes, or at various mid height outlets, or to lower, floor directed
outlets, or both. The mid height outlets are often called "air conditioning" outlets
and the floor outlets "heater" outlets, based on the temperature of the air which
is generally thought to be most comfortable at those locations, although air of any
temperature can be directed through any outlet.
[0003] The temperature of the air that ultimately reaches any outlet is generally determined
by a so called reheat and air mix system, using the evaporator and heater in series.
A so called temperature valve selects and divides the air flow through hot and/or
cold sources and, again, is typically a swinging flapper door. The evaporator is the
larger of the two heat exchangers, and extends across the entire width of the housing,
so that all the forced air passes through it first, regardless of whether the evaporator
is cold and enabled, or switched off. The heater, downstream of the evaporator, is
significantly smaller, so that cooled (or, at least, unheated) air that has passed
through the evaporator can be selectively passed through, or diverted around the heater.
[0004] A typical prior art HVAC module with reheat and air mix is shown in Figure 1. The
housing 10 contains a conventionally sized and located evaporator 12 and heater 14.
For better analysis of the workings of the module, the interior of the housing 10
can be conceptually divided up into four quadrants, A, B, C and D, based on the space
envelope that is inevitably occupied by the evaporator 12 and heater 14. The larger,
upstream evaporator 12 occupies all of both the lower and upper upstream quadrants
A and B. The smaller, downstream heater 14 occupies only the lower, downstream quadrant
C, while leaving the upper, downstream quadrant D essentially empty. Quadrant D does
provide space for the swinging motion of a temperature valve door 16, however, which
determines the final air temperature by determining the degree to which air that has
passed first through the upstream evaporator 12 is heated.
[0005] The degree of heating of the air flow is varied not by varying the temperature of
the heater 14, which has a basically constant flow of hot engine coolant through it,
but by varying the proportion of air flow over and through it. Temperature door 16,
in conjunction with a baffle 18 in front of the downstream face of the heater 14,
is moved so as to selectively block all air flow through, or permit all air flow through,
or partially permit air flow through, the heater 14. Any air flowing through the heater
14 is then routed up the back face of heater 14 and into a mixing chamber area, generally
denoted at E, which is external to the four quadrants just described. Within the mixing
chamber E, any air that has passed straight through the evaporator 12 is mixed with
any air that has been routed through heater 14 (as determined by the position of temperature
door 16), to attain a final intermediate temperature. From the mixing chamber E, tempered
air is then routed through whichever outlet or outlets the operator selects, including
upper defroster outlet 20, mid level "A/C" outlet 22, or floor directed "heater" outlet
24.
[0006] While the basic reheat system just described has worked well for years, smaller cars
present a need for more compact modules and housings. Swinging valve doors inevitably
need a semi cylindrical volume within which to move, and are also inherently non linear
in their response. That is, they tend to behave as either totally open or closed,
and do not do well and providing a "partially open" condition. So called "film valves",
in which a rolling belt with a central opening provides a precisely sized flow path
and improved linearity of air flow, are seeing increased use as a response to the
linearity issue.
[0007] Examples of film valve systems may be seen in USPN 5,326,315 and 5,154,223. In general,
however, such systems still mix the air well downstream of the heater, and well outside
of the minimal space envelope that is inevitably occupied by the evaporator and heater.
The space between the evaporator and heater is typically empty, and not occupied by
any particular structure. In one case, a film belt is located in the space between
the evaporator and heater, as seen in USPN 5,162,020. Even there, however, the mixing
zone is located well downstream of the heater, so the use of a film valve per se does
not do much to make the overall module more compact, even if it is more precise in
the determination of final air temperature.
[0008] Another recent design trend has been the attempt to save space by integrating the
HVAC module into the structure of the car itself, especially by using the instrument
panel, cross car structural beams, or both to provide air flow duct work. For example,
in co assigned USPN 5,709,601, the air ducts and HVAC module are both housed beneath
the dashboard assembly. Because of the width of the HVAC module, the entire dashboard
assembly is correspondingly quite wide as well. While this has potential for incorporation
into larger mini vans and SUVs, it is not potentially as useful in small cars. Earlier
patents, such as USPN 4,391,465; 4,733,739; and 5,005,898 have all proposed similar
designs, but have all gone abandoned for non payment of maintenance fees. Clearly,
without a more compact design for the HVAC module itself, its integration and incorporation
into the vehicle body structure will be limited.
SUMMARY OF THE INVENTION
[0009] A compact air conditioning module in accordance with the present invention is characterized
by the features specified in Claim 1.
[0010] The width of the basic housing module disclosed is significantly reduced, with the
upper downstream quadrant serving as the final air mixing chamber. This is made possible
by the use of a novel film type temperature valve, located in the otherwise unused
space between the evaporator and heater, and an air flow diversion passage that routes
the heater air flow back and up into the upper downstream quadrant, where it is mixed
with any air flow that has passed straight through the evaporator. The reduced width
of the module housing allows it to be more easily integrated into a vehicle body cross
beam.
[0011] In the preferred embodiment disclosed, the evaporator and heater are of basically
conventional size and orientation, with the heater running diagonally across the upstream
lower quadrant. A first face of the heater is directed generally upwardly and toward
the evaporator, while the opposed face is directly downwardly and forwardly. The novel
temperature valve includes a film belt located between the evaporator and heater in
a basic V shape, with an upstream leg that divides the upstream and downstream quadrant
pairs and a downstream leg covers the first face of the heater. A single opening in
the film belt can be run back and forth between the two legs of the V so as to selectively
block or permit flow through the evaporator and heater in inverse proportion. An air
flow diversion passage runs from the lower upstream quadrant to the lower face of
the heater, so that any air blocked by the film belt from just passing straight through
the evaporator is run in reverse flow through the heater, back and upwardly into the
upper downstream quadrant. There, it is mixed with any air that has passed straight
through the evaporator to attain a net final temperature. No mixing chamber outside
of the basic heat exchanger space envelope is needed, thereby reducing the overall
width of the housing module significantly.
[0012] In the embodiment disclosed, a film belt mode valve is also used, oriented in an
L shape that is opposed to the temperature valve, thereby effectively confining the
mixed air within the upper downstream quadrant. Openings in the mode valve belt are
also shifted back and forth to selectively direct air from the mixing chamber to the
desired outlet. The use of two film belt type valves, located as they are on or within
the boundaries of the heat exchanger space envelope, serves to keep the housing module
as compact as possible, so that it can be more easily structurally integrated within
a cross car structural beam or the like, eliminating the need for additional air flow
duct work.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] These and other features of the invention will appear from the following written
description, and from the drawings, in which:
Figure 1 is a cross section through a prior art module and housing;
Figure 2 is a perspective view of the vehicle occupant or rear side of a preferred
embodiment of a compact housing made according to the invention, and the cross car
beam into which it can be integrated;
Figure 3 is perspective view of the opposite or front side of the structure shown
in Figure 2;
Figure 4 is a perspective view like Figure 1, but showing the lower part of the housing
disassembled, to reveal internal structure of the housing and of the beam;
Figure 5 is a perspective view of just the housing, with the top cover of the housing
removed;
Figure 6 is an exploded perspective view of the various components included in Figure
5;
Figure 7 is a perspective view of the frame supports for the two film belts;
Figure 8 is a flat view of the temperature valve film belt in a rolled out condition;
Figure 9 is a flat view of the mode valve film belt in a rolled out condition;
Figure 10 is a side cross sectional view of the two film belts and their supporting
frames;
Figure 11 is a view taken along the line 11-11 of Figure 12, showing the so called
defrost mode, in which fully hot air is directed primarily to the defrost outlets,
and slightly into the floor directed outlets as well;
Figure 12 is a view like Figure 11, but showing the so called defog mode, with mid
temperature air directed slightly to the defrost outlets, but mostly to the floor
outlets;
Figure 13 is a view like Figure 12, but showing the full heater mode, with full hot
air directed essentially all to the floor outlets, with only a so called "heater bleed"
being directed to the defrost outlets;
Figure 14 is a view showing the so called bi level mode, with mid temperature air
directed partially to the mid level outlets and partially to the floor outlets; and
Figure 15 is a view like Figure 14, but with fully cold air now being directed just
to the panel outlets.
DETAILED DESCRIPTION OF THE INVENTION
[0014] Referring first to Figure 2, a preferred embodiment of an HVAC module housing according
to the invention is indicated generally at 30, and shown from the rear or occupant
side as it is incorporated in a cross car structural beam, indicated generally at
32. Beam 32 is capable of being formed from non metallic, sheet molded composite or
injection molded plastic parts. This is because of a generally W shaped stiffener
vibration welded or glued within it that gives it sufficient strength to replace a
conventional steel or aluminum beam. The stiffener, coincidentally, divides the interior
space of beam 32 into several lengthwise chambers which can conveniently provide air
flow ducts for an HVAC system. Here, a wider, rear passage 34 is used to direct air
to the sides and into the occupant space, while a narrower, front passage 36 is used
to direct air to the sides for side window defrosting. Structural beams like beam
32 have been proposed to support HVAC modules beneath, with the air flow therefrom
directed up and into channels within the beam. However, such beams have a limited
width W, which makes it impractical to physically incorporate the generally much wider
HVAC housings directly into the beam. It is more feasible to simply hang the HVAC
modules beneath the beam in the vertical direction V, which is not so limited. The
housing 30 made according to the invention is compact and narrow enough to allow at
least its upper portion to be directly integrated into the beam 32, as will appear
below.
[0015] Referring next to Figures 3, 4 and 6, housing 30 is shown from the front and rear,
removed from beam 32. In general, housing 30 is open at the top, and of a compact
width W' close enough to the width of beam 32 to allow part of the beam 32 to close
off the top of housing 30, and thereby be successfully integrated into the overall
structure. Specifically, incorporated into the center of beam 32 is a top cover 38
formed of the same material as beam 32. Top cover 38 has a front shelf 40 that extends
forwardly far enough to cover the top of evaporator 12, but the majority of it has
the general shape of a highly truncated pyramid so as to fit closely up into the center
of beam 32. There, it is fixed in place by sonic welding, adhesive, or some other
secure method to become, in effect, an integral structural part of beam 32. Top cover
38 to contains several outlets and inner divider walls aligned with the beam passages
34 and 36 so as to direct forced air that enters cover 38 from housing 30 into the
passages and/or direct it elsewhere into the passenger compartment. At that point,
the forced air will have already attained a final mixed temperature within housing
30, as detailed below. Two rear panel outlets 42 face toward the occupant, and two
side panel outlets 44 open into each side of the rear beam passage 34. Two front defroster
outlets 46 face toward the non illustrated windshield, and two side defroster outlets
48 open into the front beam passage 36. A central, lengthwise divider wall 50 separates
the panel outlets 42 and 44 from the defroster outlets 46 and 48. A central, widthwise
divider wall 52 segregates each side of the rear beam passage 34, providing a multi
zone air flow capability, as detailed below.
[0016] Referring next to Figures 5 and 6, the housing 30 is basically an open ended, hollow
plastic box, molded of the same plastics materials as current HVAC housings. As opposed
to the top cover 38, housing 30 is not directly integral to the beam 32, and so need
not be stiff enough to be structurally integrated into it. The walls of housing 30
are closed, but for a series of three floor duct outlets 54, which open into other
ductwork described below. As noted, the top end of housing 30 is eventually closed
by the beam integral top cover 38, while the bottom end is closed by a structure described
below, which provides an additional function beyond simple closure. A conventionally
sized and located evaporator 56 is large enough to span substantially the entire width
and height of the inside of housing 30. A conventionally sized and located heater
58 is spaced downstream from evaporator 56, and is equally wide, but significantly
shorter. As disclosed, the heater 58 is slanted slightly away from the evaporator
56, diagonally across the lower downstream quadrant C, with an upper face oriented
generally toward the evaporator 56 and an opposed lower face. Seated inside of housing
30, between the two spaced apart heater exchangers 56 and 58, is a generally V shaped
temperature belt support frame, indicated generally at 60. Diagonally opposed to frame
60 is a generally L shaped mode belt support frame, indicated generally at 62. Details
of the structure and location of the two support frames 60 and 62 are given next.
[0017] Referring next to Figures 7 and 8, the temperature belt support frame 60 is a rigid
plastic molding with a substantially symmetrical V shape and an included angle of
approximately forty five degrees. In the upstream leg of the V, a center cold air
window 64 is flanked by a pair of same sized, centrally ribbed side cold air windows
66. In the downstream leg of the V, a central hot air window 70 is flanked by a pair
of same sized, centrally ribbed side hot air windows 72. A temperature valve film
belt generally and collectively indicated at 74 is adapted to be mounted to frame
60, and is comprised of three narrower and separate belts, including a central belt
74c flanked by two side belts 74s. The central belt 74c has a central opening 76c,
substantially matched in size to the support frame central windows 64 and 70. Each
side belt 74s has a centrally located opening 76s, substantially matched in size to
the support frame side windows 66 and 72.
[0018] Referring next to Figures 7 and 9, the mode belt support frame 62 is also rigid plastic
molding, but with a general L shape having a ninety degree included angle. In the
vertical leg, a central window 78 is flanked by a pair of identical side windows 80.
In the horizontal, upper leg, a pair of identical ribbed panel outlet windows 82 is
separated by a lengthwise rib 84 from a line of five similarly sized defroster windows
86. The central area between the panel outlet windows 82 is solid. A mode valve film
belt 88 adapted to be mounted to frame 62 is a single belt with a first central opening
90c. The first central opening 90c is flanked by a pair of slightly shorter first
side openings 90s. Mode belt 88 also has a second set of similarly sized openings
92c and 92s that are axially spaced from the first set of belt openings 90. The mode
belt 88 is a single belt, but is cut by a pair of parallel clearance notches 93.
[0019] Referring next to Figures 10 and 11, and back to Figure 6, the temperature film belts
74c and 74s are mounted to the outside of their support frame 60 by rollers 94, with
the side belts 74s on the outboard sides of the frame 60, and the center temperature
belt 74c between. The belts 74c and 74s are capable of being rolled back and forth,
singly or in unison, so as to register the various belt openings with their respective
aligned frame windows just in the upstream leg of the V, or just the downstream leg,
or some inverse proportion of each (1/3-2/3), as is described in more detail below.
Likewise, the mode film belt 88 is mounted to the inside of its support frame 62 by
three rollers 96, with the openings 90s and 92s located at the outboard sides of the
frame 62 and with the central openings 90c and 92c between. The two frames 60 and
62 are basically diagonally opposed, as best seen in Figure 10. As best seen in Figure
6, a parallel pair of so called splitter walls 98 are closely captured between them,
aligned with the mode belt clearance slots 93, to allow unhindered belt motion. These
provide the potential for selective delivery of individually tempered air to the driver
side, passenger side, or straight out into the occupant compartment. The splitter
walls 98 do not affect the basic compactness of the invention, however, as they are
contained within otherwise empty space.
[0020] Referring next to Figures 2, 3 and 11, the assembly of the various components described
above is described. Evaporator 56 and heater 58 fit within housing 30 in a conventional
orientation. The temperature belt support frame 60, with its belts 74, is seated in
the space between the evaporator 56 and heater 58, with its upstream leg parallel
to the upstream face of the evaporator 56 and with its downstream leg parallel to
and covering the upper face of the heater 58. The support frame 62 for the mode valve
belt 88 is seated within the housing 30 diagonally opposed to the temperature belt
support frame 60, generally forming a four sided enclosure therewith. The central
and side windows 78 and 80 are registered with the three floor duct outlets 54 of
housing 30. Housing 30 with its various internal components is joined and sealed to
the underside of the top cover 38 by any secure method, either permanent fixing such
as adhesive, or, more conveniently, by removable fasteners. As this is done, the lengthwise
divider wall 50 within top cover 38 seats within the rib 84, and the top of the evaporator
is covered by the front shelf 40. Divider wall 50 segregates the outlets 42 and 44
in cover 38 from the outlets 46 and 48. In addition, in the embodiment disclosed,
the two side panel outlets 44 are segregated from one another by the perpendicular,
widthwise divider wall 52. The defroster windows 86 on the other side of the lengthwise
divider wall 50 open only to the various defroster outlets 46 and 48. The underside
of housing 30 is closed by a bottom cover 100, which is spaced from the lower face
of heater 58. Completing the assembly, a series of three floor directed ducts 102
are fitted to the housing floor duct outlets. The centermost of these, preferably,
would be run under the front seat and into the back seat passenger space.
[0021] Referring next to Figures 2 and 11, and back to Figure 1, the basic construction
and internal component orientation of the invention can be compared to the prior art
module design described above. The two evaporators 12-56 and two heaters 14-58 have
an essentially equivalent size and orientation within the two housings 10-30. Consequently,
the interior of housing 30 may also be conceptually divided up into the same four
quadrants A-D, defining the space envelope that is inevitably occupied by the two
heat exchangers 56 and 58. The temperature valve support frame 60 basically divides
the lower upstream quadrant C from the two upstream quadrants A and B, and is located
in space unoccupied in the Figure 1 design. The mode valve support frame 62 lies on
the upper boundary of the upper downstream quadrant D, without extending outside of
it. Therefore, housing 30, by contrast to conventional housing 10, does not extend
widthwise appreciably outside of the basic, minimally required space envelope occupied
by the heat exchangers, although bottom cover 100 does extend lower in the vertical
direction. Because housing 30 is more compact in the widthwise direction, its top
can be closed by a top cover 38, the majority of which can be fitted up and into the
relatively narrow beam 32. The internal components within housing 30, oriented as
the are, cooperate with the internal structure of the beam 32 into which the top cover
38 in integrated to provide various airflow modes and temperatures described in detail
next.
[0022] Referring next to Figures 11 through 15, the relative location of the internal components
and the resulting air flow (shown by arrows) is illustrated for various modes and
temperatures. In general, a mode can be considered primarily a function of selected
air outlet position, be it windshield directed (defrost and defog), floor directed
(heater) or midlevel, panel outlet directed ("a/c"). Air outlet position, in turn,
is a function of the position of mode belt 88, which can be deliberately selected
by a vehicle occupant, typically the driver. Secondarily, mode involves a selection
of whether the evaporator 56 is activated or not (the heater 58 being always hot).
The evaporator 56 activation will preferably be an automatic default of the mode selection,
however, not an independent choice as such. Moving through Figures 11 and 15, the
mode belt 88 is being progressively rolled "up" or to the left, with the modes scrolling
through defrost, defog, "heater" , bi level and "air conditioning." The modes "heater"
and "air conditioning" are really terms of art in so far as the temperature of air
that is selected may in fact be wide ranging, and not just very hot for "heater" or
very cold for "air conditioning". The temperature of air for any mode is chosen independently
on the basis of the position of the temperature belts 74s and 74c. Component position
and air flow for each mode is described in detail below.
[0023] Referring next to Figures 2 and 11, the defrost mode is illustrated. With the choice
of defrost mode, the mode belt 88 is rolled to the position where the second set of
mode belt openings 92c and 92s are completely aligned with the support frame defrost
windows 86, and the panel outlet windows 82 are completely blocked by solid portions
of the mode belt 88. In addition, the support frame windows 78 and 80 and partially
aligned with the mode belt first set of openings 90c and 90s respectively. The control
system would also logically be configured, for defrost mode, so as to move all of
the temperature belts 74s and 74c in unison to the same position, which, as illustrated,
is a "full hot" position that completely aligns the temperature belt openings 76c
and 76s with their respective support frame hot air windows 70 and 72. Only the side
openings 76s and side hot air window 72 show in the particular cross section at the
point where it is taken, however. Conversely, the cold air windows 64 and 66 are entirely
closed and blocked by the solid downstream leg of the temperature film belts 74s and
74c, so that the exit face of the evaporator heater 56 is blocked. All entry air first
passes through the evaporator 56, which is activated, so as to assure that the entry
air is dehumidified before being reheated. Because the cold air windows 64 and 66
are blocked, all air that has passed the evaporator 56 is forced down out of the bottom
of quadrant A, into the diversion passage formed by the bottom cover 100, and back
up into quadrant D. In effect, the air flows in reverse through the heater 58. There
is no cold air to "mix" with the dried, heated air in quadrant D, so it remains hot
and flows mostly up through the defrost windows 86 and ultimately into the top cover
38. From there, hot air flows out through the front defrost outlets 46, where it acts
on the windshield, and through the side defrost outlets 48 and in both directions
to the sides, through the narrower, front beam passage 36, to side glass surfaces.
A small fraction of the hot air in quadrant D "bleeds" through the slightly open windows
78 and 80, through the floor duct outlets 54 and into the floor ducts 102.
[0024] Referring next to Figures 2 and 12, the "defog" mode can be more briefly described,
with the Figure 11 "defrost" mode just described serving as an initial starting point.
Most significant, as compared to the Figure 11 position, is that the mode belt 88
has been rolled "up" slightly, or to the left. The shifting of belt 88 to the Figure
12 position puts less of the second set of openings 92 in registry with the defrost
windows 86, and more of the first set of openings 90 in registry with the windows
78 and 80. Consequently, as compared to pure defrost, more air flows out through the
floor duct outlets 54 and into the floor ducts 102. The temperature belts 74c and
74s have been rolled up so as to register their belt openings 76c and 76s about half
and half with their support frame cold air windows 64, 66 and the hot air windows
70, 72. This allows for about half diverted and reheated air flow up and through heater
58 as just described, and about half straight through air flow through the evaporator
56, which would still be activated for dehumidification. As with other modes, any
temperature, that is, any position of the temperature belts 74s and 74c could be chosen,
but the split flow shown better illustrates the temperature mixing. The two split
air flows reconvene and are mixed in quadrant D. It should be noted that each of the
split air flows has started up into quadrant D from a significantly low location,
around the bottom of the V, in effect, and so has ample space and time within which
to mix. Also, the slanted orientation of the heater 58, coupled with the reverse flow
of air through it, forces the heated air stream slightly back and into the cold air
stream through the evaporator 56, aiding in the mixing process.
[0025] Referring next to Figure 13, the heater mode has been selected, and with full hot
air. The control system would now preferably deactivate the evaporator 56. The mode
belt 88 has been rolled up progressively farther from the Figure 12 position, so as
to put only a very little of the second set of openings 92 in registry with the defrost
widows 86, and so as to put the first set of openings 90 fully in registry with the
windows 78 and 80. Only the side heater window 80 shows in that particular cross section,
however. As opposed to defrost and defog air, where only hot (or at least, "reheated")
air would be a logical choice, there is the capability, in the embodiment disclosed,
for different vehicle occupants to select different temperatures for the air flow
that is ultimately exiting the floor ducts 102, or the panel outlets 42 and 44, or
both. This capability is provided by the separation of the temperature belt 74 into
the three independently movable belts 74c and 74s, working in conjunction with the
splitter walls 98 and the widthwise divider wall 52. If an occupant specific temperature
selection were not needed, then the belts 74s and 74c would simply be consolidated
into one belt 74, with the same exact openings 76c and 76s, and the splitter walls
98 and widthwise divider wall 52 left out. Figure 13 illustrates the situation where
at least the passenger side occupant has chosen full hot air. The vehicle control
system would preferably shut off the compressor and evaporator 56, as indicated above,
and would also roll the passenger's side temperature belt 74s to the position shown,
where the opening 76s is fully registered only with the side hot air window 72, and
is completely blocking the side cold air window 66. Air passing through the deactivated
evaporator 56 remains at ambient temperature, and is all diverted down through the
bottom cover 100 and up through the heater core 58, where it is heated, and where
it is blocked from flowing to the side by the splitter window 98. Again, while there
is no "cold" air to mix, as shown, the temperature belt 74s could be positioned so
as to allow some ambient temperature air to pass straight through the evaporator 56
and mix with the heated air. Mixed or not, the hot air then flows mostly through the
open side heater window 80, through the aligned floor duct outlet 54, and down through
the floor directed duct 102. It should be kept in mind that, given the fact that there
is a single mode belt, air will also be flowing through the central window 78 and
through the other side heater window 80 on the driver side, but with a temperature
determined by the position of the other temperature belts 74c and 74s. A small proportion
of air "bleeds" through the defrost window 86, as well, so as to assure some windshield
defogging always exists on a default basis.
[0026] Referring next to Figure 14, the mode belt 88 has been rolled up even farther from
the Figure 13 position so as to split the openings approximately 50-50 between the
panel outlet windows 82 and the windows 78 and 80, the so called "bi-level" mode.
The terminology refers to the split in outlet level for the exiting air. The vehicle
control system would preferably automatically reactivate the evaporator 56 in bi level
mode, but the temperature of the air ultimately provided would depend on the extent
to which air passing through the evaporator 56 is diverted up and through the always
hot heater 58 for reheat, or not. Here, the passenger side occupant (at least) has
selected a temperature setting that puts at least the passenger's side temperature
belt 74s in the position shown, so as to divert about half of the air flow down and
up through the heater 58. Uniquely to the bi-level mode, thorough mixing of the air
streams is not needed or desired, with the hot air stream flowing up through the heater
58 flowing preferentially through the floor duct outlet 54 and floor duct 102 on the
passenger side, and with the air stream passing directly through the evaporator 56
flowing preferentially through the panel outlets 42 and 44 (at least those panel outlets
42 and 44 on the passenger side, since those on the driver side may receive a different
temperature air). Some air does mix, of course. This stratification of air flow is
intended for a cool but sunny day, where cooler air to the head and chest area of
an occupant is desired, but warmer air to the feet. The particular slanted, low orientation
of the heater 58 disclosed aids in that air temperature split or stratification.
[0027] Referring next to Figure 15, the relative location of the internal components is
illustrated for the so called cold air or "a/c" mode. The control system of the vehicle
would provide, of course, that the compressor and evaporator 56 be activated. The
mode belt 88 has been rolled even farther up, from the Figure 14 position, to the
position where its first set of openings 90 are all completely registered with the
its support frame panel outlet windows 82. The second set of openings 92 are now completely
rolled up on the uppermost roller 96. The other mode belt support frame windows 80
and 86 are completely blocked off by solid portions of the mode belt 88. Here, full
cold temperature is shown, and given that temperature selection, at least the passenger
temperature side belt 74s is rolled up so as to completely align the side belt opening
76s with the support frame cold air window 66. Conversely, since the cold air window
66 is entirely open, the opposed hot air window 72 is entirely closed by the downstream
leg of the temperature film belt 74s, so that the upper face of the heater 58 is blocked.
All air cooled by the evaporator 56, in turn, passes straight through the passenger
side cold air windows 66 and the aligned temperature belt side opening 76s. No air
is able to pass through the heater 58, since its upper face is blocked. The cold air
passing through the passenger side belt opening 76s is also confined and prevented
from blowing over to the other, driver's panel outlet window 82 by the adjacent splitter
wall 98. It should be kept in mind that all the belts 74 could be simultaneously moved
to the same position. Cold air passing the temperature belt(s) 74 is forced through
and up into the fourth quadrant D, but there is no diverted hot air with which to
mix. Instead, the fully cold air passes through the panel outlet window 82 on the
passenger side, and up into the top cover 38, and effectively into the interior of
the beam 32. At that point, the cold air is blocked from flowing toward the driver
side by the interposed widthwise divider wall 52, and is blocked from flowing forward
to the defroster outlets 46 and 48 by the lengthwise divider wall 50. Consequently,
from inside the top cover 38, cold air can pass only through the passenger's side
panel outlet 44 (and from there, in one direction through the beam rear passage 34)
and through the passenger's rear panel outlet 42. In addition, in the "a/c" mode,
the longer central belt opening 90c would act to leave the central window 78 open,
although that does not show in the particular cross section of Figure 15. The flow
through the central window 78 allows some air flow out through the central floor duct
outlet 54, center floor duct 102, and to the rear passenger space. Again, if the multi
zone capability were not needed, then the basic air flow shown in Figure 15 would
be the same, but the three temperature belts 74s and 74c would operate as one (or
in fact, be one belt), and the splitter walls 98 and the widthwise divider wall 52
would be eliminated.
[0028] Modifications in the preferred embodiment disclosed could be made. The fundamental
advantage of the invention as disclosed is the relative orientation of components,
and especially the location of the temperature belt 74, that allows the upper downstream
quadrant D to serve as the air mixing chamber, with the consequent compactness of
the whole housing 30. As an alternative to the tipped, diagonal location shown, the
heater 58 could be located almost in a horizontal orientation, but still all within
the lower downstream quadrant C, and still with its first or upper face oriented generally
toward the quadrant D. The air flow through heater 58 would still be the reverse of
the normal flow, that is, up through the heater 58 and into quadrant D. In that alternative
case, the two legs of the temperature belt(s) 74 would be oriented more in an L shaped
than a V shaped configuration, but the upstream leg thereof would still act to separate
the upstream (A,B) from the downstream (C,D) quadrants, and the downstream leg thereof
would still act to cover the first, upper face of the heater 58. The diagonal orientation
of the heater 58 does allow a wider core to fit within a give size quadrant C, however.
As already noted, the splitter walls 98 and the separation of the temperature belt
74 into three separate, independently movable belts could be eliminated, if the individual
air temperature selection capability were not desired. If a stiff enough temperature
belt material could be found to be self supporting, then the support frames 60 and
62 could be eliminated. The frames 60 and 62 allow more flexible belt material to
be used, however, as well as providing a convenient framework for the addition of
the splitter walls 98. Different mode valves could potentially be used, in place of
the mode belt 88. However, the particular L shaped mode belt 88 and supporting frame
62 shown, by virtue of the fact that they lie on the upper and rear border of the
"D quadrant," diagonally opposed to the temperature belt(s) 74, cooperate uniquely
with the V shaped temperature belt 74 to capture the air flows within the D quadrant
before they exit to the selected outlets. Therefore, it should be understood that
it is not intended to limit the invention just to the embodiment disclosed.